OSCODA, MI -- The federal government is reopening a 16-year-old health report on the former Wurtsmith Air Force Base in Oscoda at the urging of legislators and veterans seeking coverage for illnesses they contend were caused by exposure to toxic chemicals.

The Agency for Toxic Substances and Disease Registry (ATSDR) says it will update the 2001 public health assessment for Wurtsmith, a Strategic Air Command nuclear B-52 bomber base in northeast Michigan which closed in 1993 at the end of the Cold War.

The ATSDR, an independent agency under the U.S. Department of Health and Human Services which operates jointly with the Centers for Disease Control, will reassess past exposure in base drinking water to trichloroethylene (TCE), a cancer-causing industrial solvent found at astonishing levels in base drinking water in the late 1970s.

The report will be ready for public review this spring, ATSDR said.

Veterans hope the updated report prods the U.S. Department of Veterans Affairs (VA) to extend disability benefits and treatment to former service members without forcing them to somehow show medical evidence that links their disability claim to TCE exposure.

For that to happen, though, the ATSDR must conclude TCE exposure likely harmed people at Wurtsmith. That has to occur before the VA would consider amending its benefits policy, according to health officials. Such an outcome may also require an act of Congress.

Wurtsmith veteran Mike Bussey of Pennsylvania considers the news a "50 percent victory" because, while the ATSDR will re-examine TCE exposure, the agency declined to assess exposure among veterans to per- and polyfluoroalkyl substances called PFAS, (also named perfluorinated chemicals, or PFCs) that were used on base.

Although the Air Force began to clean up TCE in base groundwater in the late 1970s, expansive local PFAS contamination only became widely known last year when the state issued a drinking water advisory for private wells in Oscoda Township.

State investigators say PFAS began contaminating the base groundwater shortly after the Air Force started using a chemical-laden firefighting foam in the 1970s. Amid redevelopment in 1997, the base connected to municipal water from the Huron Shore Regional Utility Authority which pulls drinking water from Lake Huron. Before that, base water came from on-site wells.

On an Aug. 10 conference call, Bussey said the ATSDR told him there wasn't enough data on PFAS exposure among veterans at Wurtsmith to cook that into an official update. Last year's discovery of high PFAS levels in old water preserved in unused fire hydrants that were never flushed after the base closed wasn't enough for ATSDR, he said.

"My response was, 'that's not good enough,'" said Bussey, who was stationed at Wurtsmith as a senior airman from 1989 to 1992. "But it wasn't taken very seriously."

The call followed months of back-and-forth between the veterans group -- which is applying for 501c3 nonprofit status under the name Veterans & Civilians Clean Water Alliance -- the Michigan Department of Health & Human Services (MDHHS), and staff members with the office of Congressman Dan Kildee, a Democrat from Michigan.

Christina Bush, an MDHHS toxicologist who has been evaluating toxicant data on Wurtsmith, said the ATSDR doesn't consider the hydrant data collected by the Michigan Department of Environmental Quality last year robust enough to calculate a past exposure dose.

PFAS compounds are still considered an "emerging" contaminant, although movement toward better scientific understanding of health impacts through human studies is gaining steam.

"Even though PFAS would not be expected to degrade over time, it's unclear whether there could be some evaporation of water or imperfect mixing" in the hydrants, she said.

With TCE, it's a different story. When the original ATSDR report was written in 2001, Bush said the agency was using an interim screening level to evaluate chronic exposure. Today, that number is about 400 times lower than what the agency used previously.

Whereas concentrations of TCE in drinking water at Wurtsmith may not have exceeded the old number, they were above the screening level the agency now uses, she said.

In 2001, the ATSDR concluded it was "unknown" whether TCE concentrations at Wurtsmith "persisted at high enough levels for long enough durations to actually pose a public health hazard." The report later notes that there is "much controversy" in the scientific community about whether TCE caused cancer in humans. Since then, the ATSDR, National Toxicology Program, Environmental Protection Agency and the International Agency for Research on Cancer have all concluded that TCE is a known human carcinogen.

The chemical is all too familiar to pollution investigators. TCE was once widely used as an industrial degreaser and dry cleaning solvent. It's present at many brownfield and Superfund sites. TCE became widely known during the Woburn, Mass., water contamination case dramatized in the book and movie "A Civil Action."

TCE was first discovered in Wurtsmith drinking water in 1977. Former Michigan Attorney General Frank Kelley sued the military in 1979, alleging that Air Force officials knew about the contamination and tried to cover up the TCE presence in base water by adding phosphates to mask the odor. The Air Force settled in 1980 and installed groundwater extraction and treatment systems to capture TCE and spilled jet fuel that still operate.

According to the 2001 report, TCE concentrations in 1977 in one of Wurtsmith's primary drinking water wells reached as high as 5,173 parts-per-billion (ppb), which is more than 1,000 times the EPA's current limit of 5-ppb for TCE in drinking water.

The number of people potentially exposed to TCE at Wurtsmith is large. In 1985, the base maintained an $80 million annual payroll with 3,600 military and civilian personnel.

Notably, the TCE levels at Wurtsmith were substantially higher than those discovered at Camp LeJeune, a Marine Corps training base in North Carolina where veterans and their families drank water polluted with TCE and other chemicals from the early 1950s to the late 1980s. According to the ATSDR, TCE levels in LeJeune drinking water reached 1,400-ppb in the 1980s.

LeJeune's drinking water contamination is considered one of the largest of its kind in U.S. history and eventually forced the VA to automatically presume diseases like adult leukemia, bladder cancer, kidney cancer, liver cancer, Non-Hodgkin's lymphoma and Parkinson's disease were caused by consuming the chemicals.

However, it took many years and President Obama's signature on federal legislation to reach that point. Wurtsmith veterans hope to someday receive similar presumptive treatment.

The Wurtsmith veterans group includes members spread around the country, many of whom are battling reproductive and immune system issues, neurological problems and "more types of cancer than you can shake a stick at," Bussey said.

The group has the ear of Kildee, whose Congressional district covers Oscoda. There have been talks with his office about legislation along the lines of the Janey Ensminger Act of 2012, which authorized the VA to extend presumptive care to LeJeune veterans and families.

Capitol Hill staffers say a bill along those lines would have to follow the current push to fund a CDC study on the health impacts of PFAS in veterans and people living near military bases. Both the U.S. House and Senate have passed language requiring such a study in the 2018 National Defense Authorization Act.

"Service members have made great sacrifices for our freedoms and we must ensure that they are taken care of, especially when they were exposed to toxic substances through no fault of their own," Kildee said in a statement.

Bussey stressed that time is not on the veterans group's side.

"You can't treat what you don't acknowledge," he said. "We need to move forward on this because too many people are sick and dying."